Scaffolds are commonly used by carpenters, painters and the like to gain access to the walls of buildings and other structures. Scaffolds can be supported by a framework extending from the ground or attached to the building wall, or can be suspended on ropes or cables using scaffold hangers or bails. The scaffold platform may include a plurality of planks typically ten to fourteen feet in length, about two inches thick and either eight, ten or twelve inches in width. In some cases the planks are connected together by cross members or the like but in many cases the planks are placed side-by-side on the supporting framework but are not connected. A scaffold platform can also be constructed as a single unitary assembly, from commonly available material such as 2".times.4" boards. Regardless of the construction, scaffold platforms are of a length, width and strength to safely accommodate one or more workers above the ground.
The scaffold platform is typically supported by a pair of spaced, generally horizontally extending support members. The support members can be of various constructions, including wooden bars, tubular metal structures or metal hangers. The size and spacing of the support members will depend upon the application, but at least two spaced support members are normally required to support the scaffold platform.
In the prior art, cleats have sometimes been nailed to the bottom sides of the scaffold planks at the ends to prevent them from sliding off the support members. In other cases, the scaffold platform has been secured to the cross members by ropes or wire. The Kornely U.S. Pat. No. 2,835,538 discloses a clamp which can be used to lock a scaffold platform to a supporting bail. These prior art techniques for preventing the platform from sliding with respect to the support members have not been satisfactory in all respects. The cleats are not convenient because they tie the planks together and interfere with moving and storing the planks. The use of ropes or the like is not only inconvenient but sometimes dangerous. A clamp of the type disclosed in the Kornely patent may not be useful with all scaffold constructions, is rather complicated and inconvenient to use, and is easily lost or misplaced when not in use. Thus, the prior art has not provided a simple and convenient method of preventing dangerous slippage between the scaffold platform and the supporting members.